Even Singaporeans at Stanford University who knew Ouyang Xiangyu did not find out for a long time that she had been arrested for trying to poison her laboratory mates.
This is another indication that the 26-year-old Agency for Science, Technology and Research (A*Star) scholarship holder found it hard to make close friends. Some suggested her insecurities could have led her to snap.
The second-year graduate student, who was trying to earn her doctorate, was arrested last November in California and charged with four counts of poisoning the drinking water of classmates at her research lab with a toxic chemical.
Stanford did not alert the rest of the campus about the incident, since Ouyang, who had been ordered to stay away from the school, was no longer an "immediate threat". University spokesman Lisa Lapin added that victims also asked that the matter be kept private.
Ouyang's compatriots at Stanford said they found out about her arrest only after she stopped responding to text messages and took down her Facebook and LinkedIn accounts.
They painted Ouyang as a shy person, who found it hard to make friends and often seemed stressed with work.
She was invited to group gatherings organised by A*Star scholarship holders and Singaporeans, but "she would often say that she was busy and couldn't join us", said a 24-year-old PhD student.
Another PhD student said he first thought Ouyang had run away from school because of stress when she could not be contacted. The 26-year-old engineering student tried to draw her out of her shell last year, saying: "If you don't talk to her, she won't take the initiative to talk to you."
In one conversation, Ouyang told him that she felt she "was not as good as her peers" at Stanford. "She asked me how I handled my work. I knew then that she was very stressed and made an effort to ask her out. But she often did not come as she was working on her project. After a while, I stopped asking."
In December, one of his friends alerted him to a notice put up on a police website regarding Ouyang's arrest. "I was shocked. From the time I've spent with her, she is not like that at all. She won't hurt a fly. Something must have snapped."
Another Singaporean acquaintance, a 26-year-old biology student, said "she would talk about how she was worried about her experiments". But he also said such worries were common among students.
Ouyang, in her statements to police, admitting putting paraformaldehyde in at least two water bottles belonging to colleagues in the lab where they worked, and sabotaging a lab mate's work. This happened between last August and November.
The former Temasek Junior College and Imperial College London student claimed that she suffered from dizzy spells which left her out of touch with reality.
A*Star is keeping track of the case.
Lawyer Jeffery Hayden, who recently took over Ouyang's case, told The Straits Times yesterday that she "appeared to be doing a bit better" when he last spoke to her. He made it clear that she has not entered any plea. Her previous lawyer had suggested she may plead not guilty due to insanity.
Additional reporting by Yeo Sam Jo and Joanna Seow